I have the same problem. Although I have not soldered in a few years, it used to be my full time job so I am pretty sure that I followed directions and soldered everything clean. Any tips??
Sounds like the power supply is protecting itself from an electrical short. With the board unplugged, use a multimeter to check continuity between power and ground. You should NOT have continuity between these two, if you do then there’s a short. Also check to make sure you soldered in the regulator the correct way.